The process of producing for example bottles for beverages includes injection-molding of a preform and blow-molding of the container is known in prior art. A major task within this field is to decrease the weight of the final container thereby maintaining the same filling volume. These light-weighting containers however come to their limits when the mechanical performance of the empty or filled container is negatively influenced, which makes the handling of the container in the production line and later during storage and transport more difficult or even impossible. The containers can deform or even get broken due to the external load, if the containers are not designed to withstand the external forces.
A further problem with light-weighting containers arises when the container is filled with fluids under pressure, e.g. with carbonated beverages. In this case the container still has to provide enough strength to withstand the internal pressure. Furthermore, the resistance of containers under vacuum is often too low.
Thin and light-weighted containers which are blow-molded from a thin preform further pose problems during the production of the preform itself. During the injection-molding of the preform the material is injected into the mold from the end cap, so that the material flows along the full preform length before forming the neck part. However, this requires a minimum wall thickness of the preform to allow the material to flow through the mold to fill the neck part.
Containers as mentioned above, for example bottles holding drinkable fluids, are usually labeled, at least with information concerning its ingredients. An easy labeling of state of the art containers is often compromised by an uneven outer surface.
It is therefore the object of the present invention to improve the prior art.
Specifically it is an object of the present invention to provide preforms and containers having less weight and thinner walls, but at the same time to provide an improved strength to withstand external load, internal pressure and vacuum, and to provide an outer surface suited for easy label application.
This object is solved by the independent claims. Further features and embodiments are subject matter of the dependent claims.